浙江南部近海小黄鱼资源分布及其与环境因子的关系

根据2015—2016年浙江南部近海4个航次的底拖网资源调查数据,利用广义可加模型分析了调查期内小黄鱼资源的分布特征及其与环境因子的关系.结果表明:浙江南部近海的小黄鱼资源主要集中在鱼山渔场,夏季为小黄鱼资源的高产期,站点平均资源密度达到500.74 kg·h^-1·km^-2.不同季节影响小黄鱼资源密度及其分布的环境因子各不相同.其中,环境因子对秋季小黄鱼资源密度的影响效果并不显著.春季,小黄鱼主要分布于水深较浅的高盐水域;夏季,水温和盐度均与小黄鱼资源密度呈负相关关系,小黄鱼主要分布于中温高盐的鱼山海域;冬季,水温与资源密度呈正相关,小黄鱼栖息于水温适宜的外侧站点水域.总体上,小黄鱼资源的分布特征符合其洄游习性,但个别环境因子与资源密度的关系难以解释,仍需进一步研究.研究结果有助于了解浙江南部近海小黄鱼群体的生活习性,以及对小黄鱼资源的养护和管理.

Distribution of Larimichthys polyactis and its relationship with environmental factors in offshore water of southern Zhejiang

Based on data collected from four trips of trawl surveys in offshore water of southern Zhejiang in 2015-2016, a generalized additive model was used to analyze the distribution of small yellow croaker (Larimichthys polyactis) and its relationship with environmental factors. The results showed that the highest resource abundance occurred in the summer trip, primarily in Yushan fishing ground with an average density of 500.74 kg·h^-1·km^-2. Environmental factors influencing the density and distribution of small yellow croaker changed with season. The effect of environmental factors on the resource density of small yellow croaker was not significant in autumn. In spring, the small yellow croaker mainly distributed in waters with high salinity, while both sea bottom temperature and salinity had negative correlation with resource density of small yellow croaker in summer, and the fish habited in Yushan waters with middle temperature and high salinity. In winter, water temperature had a positive relationship with resource density of small yellow croaker which primarily distributed in waters of outside stations with suitable temperature. Generally, the distribution characteristic of small yellow croaker accorded to its migration habit. It was hard to explain the relations between environmental factors and resource density of small yellow croaker, which needed to further study. The results are helpful for understanding the living behavior and the conservation and management of the small yellow croaker stock in offshore water of southern Zhejiang.